JUST WATCHED

Obama, Putin greet with long handshake

MUST WATCH

Story highlights

Russia and the United States at odds over Syria, which allegedly used chemical weapons

The United States is weighing a possible military strike to punish Syria's Bashar al-Assad

Russia is a major Syrian ally and doubts whether chemical weapons were used as alleged

Obama will also meet with Chinese and French presidents at G-20

President Barack Obama and his Russian counterpart Vladimir Putin will have an opportunity to speak "on the margins" of the G-20 summit in Russia, a White House official said.

The development is a significant departure from what senior administration officials had said previously about Obama's trip to the international forum in St. Petersburg, noting that there would not be an information meeting.

The president left Washington on Tuesday night.

The United States and Russia are currently squaring off over the bloody civil war in Syria.

Obama has sought congressional authorization for a limited military strike to punish President Bashar al-Assad's regime for its alleged use of chemical weapons against its own people earlier this month.

MUST WATCH

JUST WATCHED

Snowden: My father doesn't represent me

MUST WATCH

Russia, a Syrian ally and major trading partner, has expressed doubts about whether those weapons were used at all. The Syrian regime denies it launched such an attack.

Russia, along with China, would be expected to block any call for any military action against Syria by the U.N. Security Council.

Obama also plans to meet formally with Chinese President Xi Jinping as well as French President Francois Hollande at the summit, the official said.

Secretary of State John Kerry hinted at a Senate hearing on Syria on Tuesday that Obama and Putin would have an opportunity to talk at the G-20.

"He will have ample opportunity to hear firsthand from President Putin," Kerry said in response to a question about Russia's involvement in Syria. "I am confident they will have a discussion about it."

The White House last month formally canceled a formal Obama-Putin meeting that was to have taken place in Moscow during this trip, citing a lack of progress in relations since Putin regained the presidency a year ago.

The decision came shortly after Russia decided to grant temporary asylum to Edward Snowden, the admitted leaker of U.S. surveillance secrets.

Although the White House acknowledged at the time that Snowden's asylum was a factor, a senior administration official told CNN that the meeting probably would have been canceled regardless.

Obama on Friday will meet with Russian civil society leaders to discuss human rights and tolerance, a White House official said. Also invited to that meeting are groups representing human rights, the environment and LGBT rights.